Resistive wires for the primers (you could get these from a hair dryer or electric heater), matchhead powder for the propellant (since black powder is too tedious to make the old fashioned way)(you can just buy those bigger boxes that have a hundred or so in them), some shot (you can make this out of some Hershey's kiss wrappers by balling them up and tapping them with a hammer until they are completely solid and hardened, before polishing them with sandpaper), a ramrod, stainless steel pipes + endcaps, a lipo battery, a dual light on/off switch for the triggers, and some wires to hook it all up (ofc). Plus some wood to strap the barrel apparatus on and for the grip. And vinyl tape.